In spite of the international concern about agricultural chemicals, the amount of such chemicals being used continues to grow. Organic chemicals registered have achieved widespread use throughout the world in the production of agronomic and horticultural crops. An agricultural chemical is any substance or mixture of substances that is useful for preventing, destroying, repelling, or mitigating any pest, or is used as a plant growth regulator, seed protectant, defoliant, or desiccant. Examples of agricultural chemicals include herbicides, algicides, plant growth regulators, defoliants and desiccants. While some herbicides may also be desiccant and defoliant agents, the action required for desiccating and defoliating is different from the action required for killing a plant.
There is considerable commercial interest in both desiccants and defoliants as harvest aids used for vegetation management. For example, in intensive cotton cultivation, the use of defoliants is necessary for effective use of plucking machines for harvesting the bolls. For reasons relating to harvesting, defoliation in the form of green leaf parts is preferred to pure desiccation and withering of the remaining plant, since otherwise the fiber quality is very adversely affected by soiling due to withered leaf residues.
Insufficient plant desiccation, however, can be a problem, especially in fields with dense growth, by allowing stem regrowth which complicates harvesting. Sequential applications 7-10 days apart are an option, provided that the grower can afford the additional cost.
The effectiveness of a desiccant is dependent on the quantity applied, the method of application, and the environmental conditions during the application. The objective of the grower or desiccant applicator is to achieve a desired result with the least amount of chemical and at the lowest cost. Therefore, a need exists for an effective and EPA approved desiccant formulation which uses less active ingredients to lessen or avoid adverse environmental effects and to reduce the cost of application.
Sometimes active agricultural chemicals are shown to be more effective in combination than when applied individually. The result is often termed "potentiation" or "synergism" since the combination demonstrates a potency or activity level exceeding that which it would be expected to have, based on a knowledge of the individual potencies of the components.
It is an object of the present invention to provide novel and better desiccants and defoliants and a novel and better method for desiccating and defoliating plants.